Online Virtual Flora of Wisconsin

Hypericum kalmianum L.

Family: Hypericaceae

Kalm's St. John's-wort

Robert Bierman

Christopher Noll

University of Wisconsin-Stevens Point, Robert W. Freckmann Herbarium (UWSP)

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Etymology: Hypericum: ancient Greek name derived from hyper, "above," and eikon, "picture," from old practice of placing flowers above an image in the house to ward off evil spirits at the midsummer festival of Walpurgisnacht, which later became feast of St. John
Plants: erect, perennial, 6"-40" tall shrub, with many branches
Leaves: often curling backward leaf drawing

Flowers: yellow, 5-parted, 3/4"-1 1/4" wide; inflorescence of 3-7 stalked flowers in a branched cluster (cyme) at the ends of the branches; blooms July-Aug.
Fruits: capsule, thin oval fruit drawing

Habitat: moist; dunes, shores; in rocky, sandy soil
Conservation Status: Native

A species with an interesting range and history in the state. In the southeast, it occurs in low prairies and fens. Populations in the Central Sands (where it is most common) are found in sedge meadows (especially Central Poor Fens), wet Jack pine or aspen savannas, moist, sandy meadows, low prairies, along lakeshores and riverbanks, in sandy ditches along roads and railroads, and sometimes in dryer oak or pine woods. Specimens from our northeastern counties have been collected along riverbanks, in boggy areas, sedge meadows, and along lakeshores. Door Co. populations are usually associated with Lake Michigan cobble or bedrock beaches but also grow in sedge meadows and dune swales. The Taylor Co. collection was collected from a ditch. This species is only found in glaciated territory throughout its range in North America and in Wisconsin is closely associated with the beds of Glacial Lakes Wisconsin, Oshkosh, and Chicago.

The recently described H. swinkianum G. Wilh. & Rericha is said to differ in its wider and longer leaves and inflorescences with more flowers. Hypericum kalmianum is quite variable and the characters used to differentiate the two could easily be influenced by growing conditions; it does not seem worth recognizing H. swinkianum.